In many conduit systems it is desired that fluid flow through the conduits be indicated, and a variety of devices have been devised for achieving this purpose. U.S. Pat. Nos. 799,603; 1,449,217; 1,756,491 and 2,691,955 show typical approaches to flow indicators.
In the past, conduit and plumbing fixtures utilizing flow indicators were necessarily of special construction and usually required that the conduit system include a special fixture having a window formed therein for the purpose of observing the flow indicator. Such special purpose fittings are expensive and bulky, and situations often exist where a flow indicator is desired, but space limitations prevent the installation of conventional flow indicators.
Popular heating systems for dwellings utilizing radiant heat employ a plurality of conduits conveying hot water which are imbedded in the dwelling floor or ceiling, often encased in the concrete forming the floor. Such heating systems require a plurality of circuits, and when balancing the circuits to closely control the flow of water through each circuit for comfort control the flow rate through each circuit is critical. The greater the flow, the hotter the particular circuit and temperature balancing can only be achieved by time consuming trial and error.
Radiant heating systems using imbedded conduits may employ conduits formed of synthetic plastic material which is transparent or translucent, such as those sold by the Wirsbo Company of Apple Valley, Minn., and it is an object of the invention to provide an inexpensive fluid flow indicator which may be used with light transmitting conduits and conventional conduit system fittings without requiring any modification to the conduit system, the conduits, or its end fittings.
Another object of the invention is to provide a fluid flow indicator of concise configuration which is inexpensive to manufacture, may be installed without special skills, and does not adversely affect the sealing characteristics of the conduit system when installed.
An additional object of the invention is to provide a fluid flow indicator which visually indicates the rate of fluid flow through a light transmitting conduit wherein the rate of rotation of the rotatable indicator flag will directly indicate the rate of fluid flow within the conduit.
Yet another object of the invention is to provide a fluid flow indicator capable of being inserted into a conventional conduit and conduit fitting without modification thereto and wherein the indicator will be positively retained against axial movement and will not jeopardize the other components of the fluid system.
In the practice of the invention the fluid flow indicator is used in conjunction with light transmitting conduits attached to an adapter by means of a conventional compression nut, ferrule and end fitting. The fluid flow indicator is primarily formed of a spiraled wire having a base portion closely received within the conduit fitting bore, and a rotatable flag extends from the base into the light transmitting portion of the conduit as to be exteriorly visible.
The indicator base is formed of a coiled wire, and at one end an enlarged coil engages with the conduit fitting and the associated adapter to axially position the indicator with respect to the associated conduit system.
A fluid flow indicator in accord with the invention can be very easily installed into a conventional fluid circuit by merely inserting the indicator into the end of the conduit fitting prior to assembling the conduit and conduit fitting to a manifold adapter. After the indicator is inserted into the conduit fitting the conduit and conduit fitting are connected to the adapter in the normal manner and once the completion of the fitting and adapter connection is finalized the positioning of the flow indicator is also achieved.